This is one of the legs of the Eiffel Tower. The bottom of the tower has a big gravel pit. I'm not sure why... perhaps to absorb bird droppings? Each leg has an elevator, though only two were open when we went. One of the legs might be a fancy restaurant.

This is a picture from one of the fancier bridges crossing the River Seine (which bisects Paris). In the background is the Eiffel Tower.